For a long while, doodling has been discouraged by teachers. It's not unusual to have seen elementary schools tapping sharply on your desk to stop you from doodling as they discussed the Civil War. Often interpreted as "proof" that one is disengaged, doodling has actually been shown recently to aid in concentration.
Check out this article from Harvard that discusses why those scribbles might actually be helping you! https://www.health.harvard.edu/blog/the-thinking-benefits-of-doodling-2016121510844
Do you agree that doodling can be beneficial, or is it just an escape from a class that you find boring?